There have been many efforts to rear aquatic species, such as shrimp larvae, post-larvae, other aquatic species larvae and juveniles. In order to successfully rear such aquatic species, careful control over the environmental conditions present in the rearing tank is necessary.
For example, the oxygen content of the water employed must be maintained at a suitable level. Additionally, a tank containing such species must be provided with superior water circulation and must have means for the removal of wastes. It is also important to agitate the entire tank bottom so that settled food particles will be resuspended and thereby become available to the growing aquatic species.
A number of systems for raising fish, shrimp and other aquatic species have been described in the patent literature. U.S. Pat. No. 3,653,358, for example, discloses a floating growing tank for fish having a closed water-tight liner filled with water and immersed in a relatively large body of water with a protective mesh surrounding the liner. A plurality of such tanks can be grouped around a service platform to provide a system for growing fish.
U.S. Pat. No. 3,886,902 discloses a recirculating fish raising tank with cleaning brushes for stirring up waste material on the bottom of each tank and filters which allow droppings to pass while retaining growing fish.
U.S. Pat. No. 4,064,836 describes an aquatic tank having flexible tank means in a shape of a closed bag held in place by a frame.
U.S. Pat. No. 4,211,183 discloses an apparatus including a fish tank with a biological filter submerged in it so that water can be recirculated through the biological filter to remove ammonia.
U.S. Pat. No. 4,221,187 discloses a rectangular tank for raising fish equipped with means for providing laminar flow through the tank and having sweeper means for removing particulate matter from the bottom of the tank.
U.S. Pat. No. 4,368,691 discloses a flowing bed method for employing loose solid particles for the removal of waste from aquatic organisms.